Coextrusion processes are used above all for the production of sausages. A corresponding coextrusion process is described, for instance, in EP 2016830B1. In that coextrusion method a paste mass, e.g. sausage meat, is covered by a gel which is cured by means of a fixing solution. After the coextrusion process the so produced sausage skein is twisted off or divided.
It happens frequently with coextruded foodstuffs that the coextruded casing, i.e. sausage casing becomes detached from the filled material, especially when the corresponding foodstuffs are heated in hot water. Such products are unacceptable to consumers.
The problem arises above all if a method is used where the casing is extruded onto a filling tube and is moved a distance towards the end of the filling tube so as to cure on the filling tube. The paste mass is then ejected through the filling tube into the casing. To minimize the coefficient of sliding friction between the filing tube and the casing to be produced a sliding agent, e.g. normal tap water, is fed between the filling tube and the extruded casing.
The sliding agent then also flows between the casing and the pasty filling material. This sliding agent may have a negative effect on the bonding between the casing and the filling material.